U.S. patent application number 14/778877 was filed with the patent office on 2016-02-18 for audio signal size control method and device.
This patent application is currently assigned to Intellectual Discovery Co., Ltd.. The applicant listed for this patent is INTELLECTUAL DISCOVERY CO., LTD.. Invention is credited to Choong Sang CHO, Byeong Ho CHOI, Je Woo KIM, Hwa Seon SHIN.
Application Number | 20160049162 14/778877 |
Document ID | / |
Family ID | 51580434 |
Filed Date | 2016-02-18 |
United States Patent
Application |
20160049162 |
Kind Code |
A1 |
CHOI; Byeong Ho ; et
al. |
February 18, 2016 |
AUDIO SIGNAL SIZE CONTROL METHOD AND DEVICE
Abstract
An audio signal size control method is disclosed. The control
method comprises the steps of: measuring a first audio signal size
which is the size of the input audio signal; scaling the input
audio signal using a preset initial peak weighting value and
measuring a second audio signal size which is the size of the
scaled audio signal; detecting a third audio signal size by
applying the first audio signal size to a preset mapping table for
maintaining the sound deviation of the audio signal to be output;
and adjusting the size of the input audio signal using the first
audio signal size, the second audio signal size, and the third
audio signal size.
Inventors: |
CHOI; Byeong Ho; (Yongin-si,
KR) ; KIM; Je Woo; (Seongnam-si, KR) ; SHIN;
Hwa Seon; (Yongin-si, KR) ; CHO; Choong Sang;
(Seongnam-si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INTELLECTUAL DISCOVERY CO., LTD. |
Seoul |
|
KR |
|
|
Assignee: |
Intellectual Discovery Co.,
Ltd.
Seoul
KR
|
Family ID: |
51580434 |
Appl. No.: |
14/778877 |
Filed: |
March 20, 2014 |
PCT Filed: |
March 20, 2014 |
PCT NO: |
PCT/KR2014/002362 |
371 Date: |
September 21, 2015 |
Current U.S.
Class: |
381/56 |
Current CPC
Class: |
H03G 7/007 20130101;
G10L 21/0316 20130101; H03G 7/002 20130101; G10L 21/034
20130101 |
International
Class: |
G10L 21/034 20060101
G10L021/034; H03G 7/00 20060101 H03G007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2013 |
KR |
10-2013-0030136 |
Apr 3, 2013 |
KR |
10-2013-0036431 |
Apr 3, 2013 |
KR |
10-2013-0036468 |
Apr 3, 2013 |
KR |
10-2013-0036475 |
Apr 3, 2013 |
KR |
10-2013-0036523 |
Claims
1. A method of adjusting an audio signal size, comprising steps of:
measuring an input audio signal size; calculating a Peek audio
signal size by applying a Peek weighting value to the measured
original audio signal size; calculating a control ratio for
adjusting an audio signal size using the original audio signal size
and the Peek audio signal size; and adjusting the input audio
signal size based on the calculated control ratio.
2. The method of claim 1, further comprising a step of checking
whether the audio signal size controlled based on the control ratio
is present in an error range of a target audio signal size.
3. The method of claim 2, further comprising a step of
recalculating the control ratio using the Peek audio signal size as
the audio signal size controlled based on the control ratio if the
audio signal size controlled based on the control ratio deviates
from the error range.
4. The method of claim 3, wherein the step of recalculating the
control ratio is repeated until the audio signal size controlled
based on the control ratio is present in the error range.
5. The method of claim 2, wherein the error range is able to be set
by a user.
6. A non-transitory recording medium on which a program for
executing the method of claim 1 in a computer has been
recorded.
7. An apparatus for adjusting an audio signal size, comprising: a
size measurement unit which measures an input audio signal size; a
weighting value application unit which calculates a Peek audio
signal size by applying a Peek weighting value to the measured
original audio signal size; a control ratio calculation unit which
calculates a control ratio for adjusting an audio signal size using
the original audio signal size and the Peek audio signal size; and
a control unit which controls the input audio signal size based on
the calculated control ratio.
8. The apparatus of claim 7, wherein the control unit checks
whether the audio signal size controlled based on the control ratio
is present in an error range of a target audio signal size and
controls the control ratio calculation unit so that the control
ratio is recalculated using the Peek audio signal size as the audio
signal size controlled based on the control ratio if the audio
signal size controlled based on the control ratio deviates from the
error range.
9. The apparatus of claim 8, wherein the control unit controls the
control ratio calculation unit so that the control ratio is
repeatedly recalculated again until the audio signal size
controlled based on the control ratio is present in the error
range.
10. The apparatus of claim 8, wherein the error range is able to be
set by a user.
11. A method of adjusting an audio signal size, comprising steps
of: measuring a first audio signal size which is a size of an input
audio signal; scaling the input audio signal using a preset initial
Peek weighting value and measuring a second audio signal size which
is a size of the scaled audio signal; and adjusting the size of the
input audio signal using the first audio signal size, the second
audio signal size, and a target audio signal size.
12. The method of claim 11, wherein the step of adjusting the size
of the input audio signal comprises steps of: calculating an "audio
signal size control ratio" by calculating a "first difference which
is a difference between the first audio signal size and the second
audio signal size" based on a "second difference which is a
difference between the first audio signal size and the target audio
signal size"; calculating a first weighting value using the
calculated "audio signal size control ratio"; calculating a new
Peek weighting value by multiplying the calculated first weighting
value and the preset initial Peek weighting value; and scaling the
input audio signal using the calculated new Peek weighting
value.
13. The method of claim 12, further comprising a step of comparing
a third difference between an audio signal size of an audio signal
scaled using the calculated new Peek weighting value and the target
audio signal size with a predetermined error range.
14. The method of claim 13, further comprising a step of adjusting
the size of the input audio signal using the audio signal size of
the audio signal scaled using the calculated new Peek weighting
value as the second audio signal size if, as a result of the
comparison, the third difference is greater than the predetermined
error range.
15. An apparatus for adjusting an audio signal size, comprising: an
audio signal size measurement unit which measures a first audio
signal size which is a size of an input audio signal and measures a
second audio signal size which is a size of a scaled audio signal
by applying a preset initial Peek weighting value to the input
audio signal; and an audio signal size control unit which adjusts
the size of the input audio signal using the first audio signal
size, the second audio signal size, and a target audio signal
size.
16. The apparatus of claim 15, further comprising a weighting value
calculation unit which calculates an "audio signal size control
ratio" by calculating a "first difference which is a difference
between the first audio signal size and the second audio signal
size" based on a "second difference which is a difference between
the first audio signal size and the target audio signal size",
calculates a first weighting value using the calculated "audio
signal size control ratio", calculates a new Peek weighting value
by multiplying the calculated first weighting value and the preset
initial Peek weighting value, and scales the input audio signal
using the calculated new Peek weighting value, wherein the audio
signal size control unit adjusts the size of the input audio signal
by scaling the input audio signal using the calculated new Peek
weighting value.
17. The apparatus of claim 16, wherein the audio signal size
control unit compares a third difference between an audio signal
size of an audio signal scaled using the calculated new Peek
weighting value and the target audio signal size with a
predetermined error range.
18. The apparatus of claim 17, wherein the audio signal size
control unit adjusts the size of the input audio signal using the
audio signal size of the audio signal scaled using the calculated
new Peek weighting value as the second audio signal size if, as a
result of the comparison, the third difference is greater than the
predetermined error range.
19. A method of adjusting an audio signal size, comprising steps
of: measuring a size of a first audio signal corresponding to a
first gate block having a predetermined gate size and a size of a
second audio signal corresponding to a second gate block having a
predetermined gate size by applying the first gate block and the
second gate block to an input audio signal; calculating a first
gate weighting value corresponding to the first gate block using
the measured size of the first audio signal and calculating a
second gate weighting value corresponding to the second gate block
using the measured size of the second audio signal; detecting a
frame in which gate handover has occurred in the first gate block
and the second gate block; interpolating a frame weighting value
from the detected frame using the calculated first and second
weighting values; and adjusting a size of an input audio signal by
scaling the input audio signal using the interpolated frame
weighting value and the first and the second gate weighting
values.
20. The method of claim 19, wherein the second gate block comprises
a gate block overlapped and moved by a predetermined size within
the first gate block.
21. The method of claim 19, wherein: the first and the second gate
blocks comprise at least one frame, and the frame determines a size
of data which is once received.
22. The method of claim 19, wherein a number of the interpolated
frame weighting values is variable.
23. An apparatus for adjusting an audio signal size, comprising: an
audio signal size measurement unit which measures a size of a first
audio signal corresponding to a first gate block having a
predetermined gate size and a size of a second audio signal
corresponding to a second gate block having a predetermined gate
size by applying the first gate block and the second gate block to
an input audio signal; a weighting value calculation unit which
calculates a first gate weighting value corresponding to the first
gate block using the measured size of the first audio signal and
calculates a second gate weighting value corresponding to the
second gate block using the measured size of the second audio
signal; a detection unit which detects a frame in which gate
handover has occurred in the first gate block and the second gate
block; and an audio signal size control unit which interpolates a
frame weighting value from the detected frame using the calculated
first and second weighting values and controls a size of an input
audio signal by scaling the input audio signal using the
interpolated frame weighting value and the first and the second
gate weighting values.
24. The apparatus of claim 23, wherein the second gate block
comprises a gate block overlapped and moved by a predetermined size
within the first gate block.
25. The apparatus of claim 23, wherein: the first and the second
gate blocks comprise at least one frame, and the frame determines a
size of data which is once received.
26. The apparatus of claim 23, wherein a number of the interpolated
frame weighting values is variable.
27. A method of adjusting an audio signal size, comprising steps
of: selecting one of manual loudness control mode, half automatic
loudness control mode, and automatic loudness control mode related
to control of an input audio signal; computing control information
for the control of the input audio signal if the selected control
mode is the half automatic loudness control mode; and displaying
the computed control information.
28. The method of claim 27, wherein the control information
comprises at least one of momentary audio signal size information,
shortterm (3 s) audio signal size information, integrated audio
signal size information, played audio signal size information,
remained audio signal size information, and recommended control
factor information.
29. The method of claim 28, wherein: the played audio signal size
information comprises information about an audio signal size of an
audio signal output so far, the remained audio signal size
information comprises information about an audio signal size which
is an insufficient or exceeded size of a played audio signal
compared to a target audio signal size, and the recommended control
factor information comprises weighting value information for
adjusting a size of an audio signal calculated using remained audio
signal size information.
30. An apparatus for adjusting an audio signal size, comprising: an
input unit which selects one of manual loudness control mode, half
automatic loudness control mode, and automatic loudness control
mode related to control of an input audio signal; a control unit
which computes control information for the control of the input
audio signal if the selected control mode is the half automatic
loudness control mode; and a display unit which displays the
computed control information.
31. The apparatus of claim 30, wherein the control information
comprises at least one of momentary audio signal size information,
shortterm (3 s) audio signal size information, integrated audio
signal size information, played audio signal size information,
remained audio signal size information, and recommended control
factor information.
32. The apparatus of claim 30, wherein: the played audio signal
size information comprises information about an audio signal size
of an audio signal output so far, the remained audio signal size
information comprises information about an audio signal size which
is an insufficient or exceeded size of a played audio signal
compared to a target audio signal size, and the recommended control
factor information comprises weighting value information for
adjusting a size of an audio signal calculated using remained audio
signal size information.
33. A method of adjusting an audio signal size, comprising steps
of: measuring a first audio signal size which is a size of an input
audio signal; scaling the input audio signal using a preset initial
Peek weighting value and measuring a second audio signal size which
is a size of the scaled audio signal; detecting a third audio
signal size by applying the first audio signal size to a
predetermined mapping table for maintaining a sound deviation of an
audio signal to be output; and adjusting the size of the input
audio signal using the first audio signal size, the second audio
signal size, and the third audio signal size.
34. The method of claim 33, wherein the input audio signal
comprises an audio signal received in real time.
35. The method of claim 33, wherein: the predetermined mapping
table is a table on which mapping is performed using linear mapping
in a region in which the first audio signal size is smaller than a
predetermined value and a table on which mapping is performed using
an equation below in a region in which the first audio signal size
is equal to or greater than the predetermined value oLKFS i = 1 ( 1
+ exp ( - LKFS i .times. w ) ) ##EQU00014## wherein iLKFS is the
first audio signal size, oLKFS is the third audio signal size, and
w is a changeable weighting value.
36. The method of claim 33, wherein the step of adjusting the size
of the input audio signal comprises steps of: calculating an "audio
signal size control ratio" by calculating a "first difference which
is a difference between the first audio signal size and the second
audio signal size" using a "second difference which is a difference
between the first audio signal size and the third audio signal
size"; calculating a first weighting value using the calculated
"audio signal size control ratio"; calculating a new Peek weighting
value by multiplying the calculated first weighting value and the
preset initial Peek weighting value; and scaling the input audio
signal using the calculated new Peek weighting value.
37. An apparatus for adjusting an audio signal size, comprising: an
audio signal size measurement unit which measures a first audio
signal size which is a size of an input audio signal, scales the
input audio signal using a preset initial Peek weighting value and
measuring a second audio signal size which is a size of the scaled
audio signal, and detects a third audio signal size by applying the
first audio signal size to a predetermined mapping table for
maintaining a sound deviation of an audio signal to be output; and
an audio signal size control unit which adjusts the size of the
input audio signal using the first audio signal size, the second
audio signal size, and the third audio signal size.
38. The apparatus of claim 37, wherein the input audio signal
comprises an audio signal received in real time.
39. The apparatus of claim 37, wherein: the predetermined mapping
table is a table on which mapping is performed using linear mapping
in a region in which the first audio signal size is smaller than a
predetermined value and a table on which mapping is performed using
an equation below in a region in which the first audio signal size
is equal to or greater than the predetermined value oLKFS i = 1 ( 1
+ exp ( - LKFS i .times. w ) ) ##EQU00015## wherein iLKFS is the
first audio signal size, oLKFS is the third audio signal size, and
w is a changeable weighting value.
40. The apparatus of claim 37, further comprising a weighting value
calculation unit which calculates an "audio signal size control
ratio" by calculating a "first difference which is a difference
between the first audio signal size and the second audio signal
size" using a "second difference which is a difference between the
first audio signal size and the third audio signal size",
calculates a first weighting value using the calculated "audio
signal size control ratio", and calculates a new Peek weighting
value by multiplying the calculated first weighting value and the
preset initial Peek weighting value, wherein the audio signal size
control unit adjusts the size of the input audio signal by scaling
the input audio signal using the calculated new Peek weighting
value.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method and apparatus for
adjusting an audio signal size played back in multimedia.
BACKGROUND ART
[0002] People are placed in various environments and exposed to
various sounds in everyday life. Sounds exposed to people are
generated by various reasons. As shown in FIG. 1, the sounds
include an environment noise that generates uneasiness when a
person hears the noise, a multimedia sound and music that makes a
person pleasant, and a sound generated when people exchange
dialogues and information.
[0003] Several sounds around people may inflict pain on a person,
may make delight a person, or may provide various pieces of
information to people depending on the size and type of a sound.
Such a reason lies in that the size and intensity of a sound
becomes a valuable numerical value which defines the degree of
acoustic fatigue and the physical properties of the sound because
the hearing structure of a person recognizes the sound through the
sound pressure level of the sound transferred through air.
[0004] A sound size (loudness), that is, one of methods for
evaluating a sound, is a subjective sound size recognized by the
acoustic system of a person when any sound is delivered to a
person's ear. The intensity of a sound is power of a sound, that
is, the intensity of an objective sound delivered to the acoustic
system of a person. In general, the intensity of a sound is
measured as a well-known decibel. In general, the intensity of a
sound of a dialogue between people is 60.about.70 dB, and the
intensity of a sound in the roadside having heavy traffic and
severe noise is about 80 dB. In general, people feel relaxed about
in a 70 dB range.
[0005] Referring to FIG. 1, a method and opportunity in which
modern people encounter audio are gradually increased. With the
development of portable multimedia audio devices, people become
able to enjoy required multimedia content and music anywhere and at
any situation. In particular, in audio, as MP3 (MPEG-1 Layer III)
emerged and the Internet was commercialized in the late 1990s,
people have become able to easily download a digital sound source
compressed in MP3 through the Internet and hear the downloaded
digital sound source.
[0006] A commercial audio sound source market has been fused with
the popularization of multimedia devices and rapidly expanded. In
order to attract people's interest as competitiveness becomes
severe in the field, a ratio of a difference (dynamic range)
between a playable maximum sound and minimum sound of an audio
sound source has been abruptly reduced and a maximum value of a
waveform has been increased, so an audio sound size has been
significantly increased. This become further intensified in the
thought "as an audio sound size is increased, people may recognize
a corresponding audio as better music."
[0007] FIG. 2(A) shows the waveform of music (pops) in 1970, and
FIG. 2(B) shows the waveform of K-pops in 2011. From FIG. 2, it may
be seen that the dynamic range of music recorded a long time again
is wider than that of a recently issued sound source. It may be
seen that the waveform of a K-pops sound source that has been
recently globalized reaches a maximum value or exceeds the maximum
value.
[0008] Accordingly, there is a need for a technology for accurately
measuring the sound size of an audio and adjusting a sound size in
a multimedia device and for a technology for adjusting an audio
sound size.
DISCLOSURE
Technical Problem
[0009] An object of the present invention is to provide a method
and apparatus capable of efficiently adjusting an audio signal size
provided in various multimedia environments.
[0010] An object of the present invention is to provide an
apparatus and method capable of adjusting an audio signal size so
that the size complies with a standard with respect to a recorded
and previously produced broadcasting program.
[0011] An object of the present invention is to provide an
apparatus and method capable of adjusting an audio signal size so
that the size complies with a standard while avoiding gate delay
attributable to the interpolation of a gate weighting value.
[0012] An object of the present invention is to provide an
apparatus and method capable of adjusting the audio signal size of
a real-time/live-obtained audio signal so that the audio signal
size complies with a standard.
Technical Solution
[0013] In accordance with a first embodiment of the present
invention for accomplishing the object, there are provided an
apparatus and method capable of adjusting an audio signal size so
that the size complies with a standard with respect to a recorded
and previously produced broadcasting program.
[0014] Furthermore, in accordance with a second embodiment of the
present invention for accomplishing the object, there are provided
an apparatus and method capable of adjusting an audio signal size
so that the size complies with a standard with respect to a
real-time/live-obtained broadcasting program.
[0015] Furthermore, in accordance with the third embodiment of the
present invention for accomplishing the object, there are provided
an apparatus and method capable of adjusting an audio signal size
while minimizing the deterioration of hearing audio sound quality
attributable to the normalization of an audio signal size.
[0016] Furthermore, in accordance with the fourth embodiment of the
present invention for accomplishing the object, there are provided
an apparatus and method for providing a new audio control function
by taking into consideration of the normalization of an audio
signal size.
[0017] A method of adjusting an audio signal size in accordance
with an embodiment of the present invention for accomplishing the
object includes steps of measuring a first audio signal size which
is the size of an input audio signal, scaling the input audio
signal using a preset initial Peek weighting value and measuring a
second audio signal size which is the size of the scaled audio
signal, and adjusting the size of the input audio signal using the
first audio signal size, the second audio signal size, and a target
audio signal size.
[0018] Furthermore, the step of adjusting the size of the input
audio signal may include steps of calculating an "audio signal size
control ratio" by calculating a "first difference which is a
difference between the first audio signal size and the second audio
signal size" based on a "second difference which is a difference
between the first audio signal size and the target audio signal
size", calculating a first weighting value using the calculated
"audio signal size control ratio", calculating a new Peek weighting
value by multiplying the calculated first weighting value and the
preset initial Peek weighting value, and scaling the input audio
signal using the calculated new Peek weighting value.
[0019] Furthermore, the method may further include a step of
comparing a third difference between the audio signal size of an
audio signal scaled using the calculated new Peek weighting value
and the target audio signal size with a predetermined error
range.
[0020] Furthermore, the method may further include a step of
adjusting the size of the input audio signal using the audio signal
size of the audio signal scaled using the calculated new Peek
weighting value as the second audio signal size if, as a result of
the comparison, the third difference is greater than the
predetermined error range.
[0021] Meanwhile, an apparatus for adjusting an audio signal size
in accordance with an embodiment of the present invention for
accomplishing the object includes an audio signal size measurement
unit which measures a first audio signal size which is the size of
an input audio signal and measures a second audio signal size which
is the size of a scaled audio signal by applying a preset initial
Peek weighting value to the input audio signal and an audio signal
size control unit which adjusts the size of the input audio signal
using the first audio signal size, the second audio signal size,
and a target audio signal size.
[0022] Furthermore, the apparatus further includes a weighting
value calculation unit which calculates an "audio signal size
control ratio" by calculating a "first difference which is a
difference between the first audio signal size and the second audio
signal size" based on a "second difference which is a difference
between the first audio signal size and the target audio signal
size", calculates a first weighting value using the calculated
"audio signal size control ratio", calculates a new Peek weighting
value by multiplying the calculated first weighting value and the
preset initial Peek weighting value, and scales the input audio
signal using the calculated new Peek weighting value. The audio
signal size control unit may adjust the size of the input audio
signal by scaling the input audio signal using the calculated new
Peek weighting value.
[0023] Furthermore, the audio signal size control unit may compare
a third difference between the audio signal size of an audio signal
scaled using the calculated new Peek weighting value and the target
audio signal size with a predetermined error range.
[0024] Furthermore, the audio signal size control unit may adjust
the size of the input audio signal using the audio signal size of
the audio signal scaled using the calculated new Peek weighting
value as the second audio signal size if, as a result of the
comparison, the third difference is greater than the predetermined
error range.
[0025] A method of adjusting an audio signal size in accordance
with an embodiment of the present invention for accomplishing the
object includes steps of measuring the size of a first audio signal
corresponding to a first gate block having a predetermined gate
size and the size of a second audio signal corresponding to a
second gate block having a predetermined gate size by applying the
first gate block and the second gate block to an input audio
signal, calculating a first gate weighting value corresponding to
the first gate block using the measured size of the first audio
signal and calculating a second gate weighting value corresponding
to the second gate block using the measured size of the second
audio signal, detecting a frame in which gate handover has occurred
in the first gate block and the second gate block, interpolating a
frame weighting value from the detected frame using the calculated
first and second weighting values, and adjusting the size of an
input audio signal by scaling the input audio signal using the
interpolated frame weighting value and the first and the second
gate weighting values.
[0026] Furthermore, the second gate block may include a gate block
overlapped and moved by a predetermined size within the first gate
block.
[0027] Furthermore, the first and the second gate blocks may
include at least one frame, and the frame may determine the size of
data which is once received.
[0028] Furthermore, the number of interpolated frame weighting
values may be variable.
[0029] Meanwhile, an apparatus for adjusting an audio signal size
in accordance with an embodiment of the present invention for
accomplishing the object includes an audio signal size measurement
unit which measures the size of a first audio signal corresponding
to a first gate block having a predetermined gate size and the size
of a second audio signal corresponding to a second gate block
having a predetermined gate size by applying the first gate block
and the second gate block to an input audio signal, a weighting
value calculation unit which calculates a first gate weighting
value corresponding to the first gate block using the measured size
of the first audio signal and calculates a second gate weighting
value corresponding to the second gate block using the measured
size of the second audio signal, a detection unit which detects a
frame in which gate handover has occurred in the first gate block
and the second gate block, and an audio signal size control unit
which interpolates a frame weighting value from the detected frame
using the calculated first and second weighting values and adjusts
the size of an input audio signal by scaling the input audio signal
using the interpolated frame weighting value and the first and the
second gate weighting values.
[0030] Furthermore, the second gate block may include a gate block
overlapped and moved by a predetermined size within the first gate
block.
[0031] Furthermore, the first and the second gate blocks may
include at least one frame, and the frame may determine the size of
data which is once received.
[0032] Furthermore, the number of interpolated frame weighting
values may be variable.
[0033] A method of adjusting an audio signal size in accordance
with an embodiment of the present invention for accomplishing the
object includes steps of selecting one of manual loudness control
mode, half automatic loudness control mode, and automatic loudness
control mode related to control of an input audio signal, computing
control information for the control of the input audio signal if
the selected control mode is the half automatic loudness control
mode, and displaying the computed control information.
[0034] Furthermore, the control information may include at least
one of momentary audio signal size information, shortterm (3 s)
audio signal size information, integrated audio signal size
information, played audio signal size information, remained audio
signal size information, and recommended control factor
information.
[0035] Furthermore, the played audio signal size information may
include information about the audio signal size of an audio signal
output so far, the remained audio signal size information may
include information about an audio signal size which is the
insufficient or exceeded size of a played audio signal compared to
a target audio signal size, and the recommended control factor
information may include weighting value information for adjusting
the size of an audio signal calculated using remained audio signal
size information.
[0036] Meanwhile, an apparatus for adjusting an audio signal size
in accordance with an embodiment of the present invention for
accomplishing the object includes an input unit which selects one
of manual loudness control mode, half automatic loudness control
mode, and automatic loudness control mode related to control of an
input audio signal, a control unit which computes control
information for the control of the input audio signal if the
selected control mode is the half automatic loudness control mode,
and a display unit which displays the computed control
information.
[0037] Furthermore, the control information may include at least
one of momentary audio signal size information, shortterm (3 s)
audio signal size information, integrated audio signal size
information, played audio signal size information, remained audio
signal size information, and recommended control factor
information.
[0038] Furthermore, the played audio signal size information may
include information about the audio signal size of an audio signal
output so far, the remained audio signal size information may
include information about an audio signal size which is the
insufficient or exceeded size of a played audio signal compared to
a target audio signal size, and the recommended control factor
information may include weighting value information for adjusting
the size of an audio signal calculated using remained audio signal
size information.
[0039] A method of adjusting an audio signal size in accordance
with an embodiment of the present invention for accomplishing the
object includes steps of measuring a first audio signal size which
is the size of an input audio signal, scaling the input audio
signal using a preset initial Peek weighting value and measuring a
second audio signal size which is the size of the scaled audio
signal, detecting a third audio signal size by applying the first
audio signal size to a predetermined mapping table for maintaining
a sound deviation of an audio signal to be output, and adjusting
the size of the input audio signal using the first audio signal
size, the second audio signal size, and the third audio signal
size.
[0040] Furthermore, the input audio signal may include an audio
signal received in real time.
[0041] Furthermore, the predetermined mapping table may be a table
on which mapping is performed using linear mapping in a region in
which the first audio signal size is smaller than a predetermined
value and a table on which mapping is performed using an equation
below in a region in which the first audio signal size is equal to
or greater than the predetermined value.
oLKFS i = 1 ( 1 + exp ( - LKFS i .times. w ) ) ##EQU00001##
[0042] In this case, iLKFS may be the first audio signal size,
oLKFS may be the third audio signal size, and w may be a changeable
weighting value.
[0043] Furthermore, the step of adjusting the size of the input
audio signal may include steps of calculating an "audio signal size
control ratio" by calculating a "first difference which is a
difference between the first audio signal size and the second audio
signal size" using a "second difference which is a difference
between the first audio signal size and the third audio signal
size", calculating a first weighting value using the calculated
"audio signal size control ratio", calculating a new Peek weighting
value by multiplying the calculated first weighting value and the
preset initial Peek weighting value, and scaling the input audio
signal using the calculated new Peek weighting value.
[0044] Meanwhile, an apparatus for adjusting an audio signal size
in accordance with an embodiment of the present invention for
accomplishing the object includes an audio signal size measurement
unit which measures a first audio signal size which is the size of
an input audio signal, scales the input audio signal using a preset
initial Peek weighting value and measuring a second audio signal
size which is the size of the scaled audio signal, and detects a
third audio signal size by applying the first audio signal size to
a predetermined mapping table for maintaining a sound deviation of
an audio signal to be output and an audio signal size control unit
which adjusts the size of the input audio signal using the first
audio signal size, the second audio signal size, and the third
audio signal size.
[0045] Furthermore, the input audio signal may include an audio
signal received in real time.
[0046] Furthermore, the predetermined mapping table may be a table
on which mapping is performed using linear mapping in a region in
which the first audio signal size is smaller than a predetermined
value and a table on which mapping is performed using an equation
below in a region in which the first audio signal size is equal to
or greater than the predetermined value.
oLKFS i = 1 ( 1 + exp ( - LKFS i .times. w ) ) ##EQU00002##
[0047] In this case, iLKFS may be the first audio signal size,
oLKFS may be the third audio signal size, and w may be a changeable
weighting value.
[0048] Furthermore, the apparatus further includes a weighting
value calculation unit which calculates an "audio signal size
control ratio" by calculating a "first difference which is a
difference between the first audio signal size and the second audio
signal size" using a "second difference which is a difference
between the first audio signal size and the third audio signal
size", calculates a first weighting value using the calculated
"audio signal size control ratio", and calculates a new Peek
weighting value by multiplying the calculated first weighting value
and the preset initial Peek weighting value. The audio signal size
control unit may adjust the size of the input audio signal by
scaling the input audio signal using the calculated new Peek
weighting value.
Advantageous Effects
[0049] In accordance with various embodiments of the present
invention, when a user fixes a multimedia device volume and hears
several audio sound sources, inconvenience and high hearing fatigue
attributable to a difference between audio sound sizes generated
between the audio sound sources can be effectively reduced.
[0050] In accordance with various embodiments of the present
invention, the size of an audio signal can be automatically
controlled so that it complies with a standard with respect to a
recorded and previously produced broadcasting program. Accordingly,
when a user fixes a multimedia device volume and hears several
audio sound sources, inconvenience and high hearing fatigue
attributable to a difference between audio sound sizes generated
between the audio sound sources can be effectively reduced.
[0051] In accordance with various embodiments of the present
invention, gate delay attributable to the interpolation of a gate
weighting value may not be generated by interpolating the gate
weighting value from a frame in which gate handover is
generated.
[0052] Furthermore, the number of interpolated gate weighting
values can be variably controlled.
[0053] In accordance with various embodiments of the present
invention, a user can control an audio signal size more easily
because information for control of the audio signal size is
provided.
[0054] In accordance with various embodiments of the present
invention, the audio signal size of a real-time/live-obtained audio
signal can be controlled so that it complies with a standard.
DESCRIPTION OF DRAWINGS
[0055] FIG. 1 is a diagram illustrating various hearing fatigue
main causes generated in everyday life.
[0056] FIG. 2 is a diagram showing examples of the waveforms of
audio signals.
[0057] FIG. 3 is a diagram illustrating a distortion phenomenon
attributable to audio data clipping.
[0058] FIG. 4 is a diagram illustrating a hearing loss attributable
to audio and noises.
[0059] FIG. 5 is a diagram illustrating the normalization of the
audio signal size of a digital broadcasting program.
[0060] FIG. 6 is a diagram showing a method of measuring the size
of an audio signal.
[0061] FIG. 7 is a graph showing an example of the frequency
response characteristics of a pre-filter.
[0062] FIG. 8 is a graph showing an example of the frequency
response characteristics of an RLB filter.
[0063] FIG. 9 is a diagram illustrating an example of the structure
of a broadcasting system for a recorded and previously produced
broadcasting program.
[0064] FIG. 10 is a diagram showing a first embodiment of a method
of adjusting an audio signal size.
[0065] FIG. 11 is a detailed diagram illustrating the first
embodiment of the method of adjusting an audio signal size.
[0066] FIG. 12 is a diagram showing a basic structure of the
computation of a loudness control ratio based on a peak value for
adjusting an audio signal size.
[0067] FIG. 13 is a diagram showing an example of the structure of
a real-time broadcasting system.
[0068] FIG. 14 is a diagram showing a second embodiment.
[0069] FIG. 15 is a detailed diagram illustrating the second
embodiment.
[0070] FIG. 16 is a diagram illustrating a method in which a live
LD control step has been added to the last stage of the first
embodiment, the second embodiment.
[0071] FIG. 17 is a diagram showing a third embodiment of a method
of compensating for the deterioration of sound quality attributable
to the adjustment of the size of an audio signal.
[0072] FIG. 18 is a diagram showing a fourth embodiment of a method
of adjusting an audio signal size in a terminal.
[0073] FIG. 19 is a detailed flowchart illustrating a method of
adjusting an audio signal size in an apparatus for adjusting an
audio signal size in accordance with a first embodiment of the
present invention.
[0074] FIG. 20 is a diagram illustrating a method of measuring the
size of an audio signal to which an audio gating method described
in ITU-R 1770-2 has been added.
[0075] FIG. 21 is a diagram illustrating gate handover in order to
describe a method of adjusting an audio signal size in accordance
with a fifth embodiment of the present invention.
[0076] FIG. 22 is a diagram illustrating the method of adjusting an
audio signal size in accordance with the fifth embodiment of the
present invention.
[0077] FIG. 23 is a diagram illustrating linear interpolation, that
is, an example of interpolation in accordance with the fifth
embodiment of the present invention.
[0078] FIG. 24 is a diagram showing an example of information
provided in half automatic loudness control mode of the second
embodiment of the present invention.
[0079] FIG. 25 is a diagram showing a method of calculating a
recommended control factor that belongs to information provided in
half automatic loudness control mode of the second embodiment of
the present invention.
[0080] FIG. 26 is a diagram showing a method of adjusting an audio
signal size in automatic loudness control mode of the second
embodiment of the present invention.
[0081] FIG. 27 is a diagram showing a method of designing a mapping
curve for calculating a mapping audio signal size (mapped LKFS)
according to FIG. 26.
[0082] FIGS. 28 to 30 are diagrams showing a comparison between the
waveform of an input audio signal and the waveform of a normalized
audio signal.
MODE FOR INVENTION
[0083] The following contents illustrate only the principle of the
present invention. Although devices have not been clearly described
or illustrated in this specification, those skilled in the art may
implement various devices that implement the principle of the
present invention and are included in the concept and scope of the
present invention. Furthermore, it should be understood that in
principle, conditional terms and embodiments listed in this
specification are evidently intended only in order for the concept
of the present invention to be understood and the scope of the
present invention is not restricted by the specially listed
embodiments and states.
[0084] Furthermore, it is to be understood that all the detailed
descriptions that list specific embodiments in addition to the
principle, aspects, and embodiments of the present invention are
intended to include the structural and functional equivalents of
such matters. Furthermore, it should be understood that the
equivalents include equivalents to be developed in the future, that
is, all devices invented to perform the same function by
substituting some elements, in addition to known equivalents.
[0085] Accordingly, it should be understood that a block diagram of
this specification, for example, is indicative of a conceptual
viewpoint of an exemplary circuit that materializes the principle
of the present disclosure. Likewise, it should be understood that
all flowcharts, state change diagrams, and pseudo code may be
substantially represented in computer-readable media and are
indicative of various processes that are executed by computers or
processors irrespective of whether the computers or processors are
evidently illustrated.
[0086] The functions of processors or the functions of various
devices illustrated in the drawings that include function blocks
illustrated as a similar concept may be provided by the use of
hardware capable of executing software in relation to proper
software, in addition to dedicated hardware. When being provided by
a processor, the function may be provided by a single dedicated
processor, a single sharing processor, or a plurality of separated
processors, and some of them may be shared.
[0087] Furthermore, a processor, control, or a term suggested as a
similar concept thereof, although it is clearly used, should not be
construed as exclusively citing hardware having the ability to
execute software, but should be construed as implicitly including
Digital Signal Processor (DSP) hardware, or ROM, RAM, or
non-volatile memory for storing software without restriction. The
processor, control, or term may also include known other
hardware.
[0088] In the claims of this specification, an element represented
as means for executing a function written in a detailed description
has been intended to include all methods of performing a function
including all types of software which include a combination of
circuit elements configured to perform the function or
firmware/microcode, and is combined with a proper circuit
configured to execute the software in order to perform the
function. It is to be understood that any means capable of
providing the function is equivalent with a thing checked from this
specification because functions provided by variously listed means
are combined and the present disclosure defined by the claims is
combined with a method required by the claims.
[0089] The above objects, characteristics, and merits will become
more apparent from the following detailed description taken in
conjunction with the accompanying drawings, and thus those skilled
in the art to which the present invention pertains may readily
implement the technical spirit of the present invention.
Furthermore, in describing the present invention, a detailed
description of a known art related to the present invention will be
omitted if it is deemed to make the gist of the present invention
unnecessarily vague.
[0090] A preferred embodiment of the present invention is described
in detail with reference to the accompanying drawings.
[0091] FIG. 3 is a diagram illustrating a distortion phenomenon
attributable to audio data clipping.
[0092] If the waveform of a sound source exceeds a permissible data
resolution range in digital data, the waveform of the sound source
is clipped, and this phenomenon is audio data clipping.
[0093] FIG. 3(A) shows a sine wave not including clipping, (B)
shows a waveform frequency characteristics not including clipping,
(C) shows a sine wave including clipping, and (D) shows a waveform
frequency characteristics including clipping.
[0094] Referring to FIG. 3, the audio data clipping phenomenon
distorts an audio signal. When the frequency characteristics of the
simple sine waveform (FIG. 3(B)) are compared with the frequency
characteristics of the clipped sine waveform (FIG. 3(D)), it may be
seen that a signal distortion component not present in a sine
waveform not including clipping as in a region indicated by a
dotted line of FIG. 3(D) is generated by audio data clipping.
[0095] Meanwhile, a problem attributable to an increase of an audio
sound size is amplified by the popularization of a portable
multimedia device. Teenagers who currently have a greatly increased
audio hearing time due to multimedia devices continue to be exposed
to a sound source having a very large audio sound size.
[0096] From FIG. 4, it may be seen that the hearing ability of
teenagers in the United States was greatly lost when portable
multimedia devices were popularized in the middle 2000s compared to
prior to the emergence of a portable multimedia device based on MP3
in the early 1990s.
[0097] Furthermore, it may be seen that noise type hearing loss
patients in Korea was increased about 50% compared to the early and
late 2000s and hearing fatigue attributable to multimedia devices
and noise environments exceeds a threshold and affects the
deterioration of a hearing function.
[0098] Accordingly, in order for people to safely live and
pleasantly enjoy audio and music during their lifetime, there is a
need for a task for lowering hearing fatigue attributable to
audio.
[0099] To this end, an embodiment of the present invention relates
to a method of accurately measuring an audio sound size and
adjusting a sound size in a multimedia device.
[0100] FIG. 5 is a diagram illustrating the normalization of the
audio signal size of a digital broadcasting program.
[0101] In Korea, an effort to reduce an audio signal size
(loudness) difference between broadcasting stations and pieces of
content through the amendment of the Broadcasting Act is in
progress. Today, programs transmitted by broadcasting have a great
difference between broadcasting companies and pieces of
broadcasting content.
[0102] FIG. 5 shows that the audio signal sizes (e.g., Channel 1:
-23.4 LKFS and Channel 2: -8.5 LKFS) of two types of music content
have a significant difference. Such a difference causes significant
inconvenience to broadcasting viewers. In order to overcome such a
problem, a standardization task under the name of a "digital
broadcasting program volume level criterion" is in progress in the
PG803 WG8034 subsidiary of the TTA.
[0103] The object of the standardization is to prepare a criterion
on which a channel/broadcasting program having a significant size
difference is made to have a normalized audio signal size (e.g.,
Channel1: -24 LKFS and Channel2: -24 LKFS) by controlling the
channel/broadcasting program based on a standardized volume
standard, as shown in FIG. 5.
[0104] The standardization may be associated with the Broadcasting
Act. If the importance and usability of the standard are very high,
the standard may propose an audio signal criterion and standard
suitable for a local situation based on ITU-1770-1/2, that is, an
internal audio signal size measurement standard. Accordingly,
techniques which may help to comply with the audio signal criterion
and standard and analysis of a current digital broadcasting signal
size will be performed.
[0105] FIG. 6 is a diagram showing a method of measuring the size
of an audio signal.
[0106] Research on a method of measuring the size of an audio
signal was started in the middle 2000s. ITU issued ITU-R BS.
1770-1, that is, a standard for the measurement of an audio signal
size, in the year of 2006. ITU-R BS. 1770-2 to which a gating
method was added was issued in the year of 2011.
[0107] The issued standard proposed only a method of measuring the
size of an audio signal and a true peak measurement method, and a
part regarding control of an audio signal size has not been
performed. So far, a part regarding a method of adjusting an audio
signal size has not been standardized.
[0108] In the method of measuring the size of an audio signal
standardized by the ITU-R, measurement is performed through a
loudness, K weighting value, relative to nominal full scale (LKFS),
such as that shown in FIG. 6.
[0109] The first module (pre-filter) of an algorithm is formed of a
secondary IIR filter in order to take into consideration an
acoustic influence according to the head of a person.
[0110] FIG. 7 is a graph showing an example of the frequency
response characteristics of the pre-filter.
[0111] The frequency characteristics of the pre-filter remove a
region of 1 kHz or less and permits a pass in a region of 1 kHz or
more based on about 1 kHz, as shown in FIG. 7. The filter
coefficient of 48 kHz data that is used in general is provided by
ITU-R BS. 1770-1 based on the head model of a spherical shape.
[0112] FIG. 8 is a graph showing an example of the frequency
response characteristics of an RLB filter.
[0113] In a second module (RLB filter), a weighting filter based on
a human's acoustic characteristic is applied. The filter is based
on a characteristic in which a person's hearing has different
sensitivity in the frequency region of an input sound, as shown in
FIG. 8(A).
[0114] For example, FIG. 8(A) shows that a person recognizes about
20 dB in 250 Hz and about 1 dB in 1 kHz based on a minimum level as
the same audio sound size. Accordingly, a band type weighting
filter has been designed so that a filter response for taking into
consideration the hearing of a person has a filter response similar
to a case where the same audio sound size contour line defined in
ISO 226 is inversely applied as shown in FIG. 8(B).
[0115] In the designed weighting filter, the weighting value of a
low frequency region was reduced, but a region of 1 kHz or more had
a relatively high weighting value compared to the low frequency
region. Furthermore, in order to simplify the weighting filter, a
region of 1 kHz or more was flatly designed. The RLB weighting
filter has a secondary IIR filter structure and provides a filter
coefficient for 48 kHz data through the ITU-R document.
[0116] Results passing through the weighting filter are converted
as in the following equation in the mean-square energy module of
FIG. 6.
z i = 1 T .intg. 0 T y i 2 [ Equation 1 ] ##EQU00003##
[0117] Energy to which a weighting value has been applied is summed
by applying a weighting value for each channel to energy of each
channel as in the following equation and then converted in decibels
by applying the sum to a log equation. A loudness, K weighting
value, relative to nominal full scale (LKFS) is used as a unit for
a sound size obtained by the following equation.
Loudness = - 0.691 + 10 log 10 i N G i .times. z i LKFS [ Equation
2 ] ##EQU00004##
[0118] In Equation 2, N is the number of channels, and G is the
weighting value of a channel.
[0119] In order to verify whether the designed audio sound size
measurement method based on ITU has been accurately designed, a
sound size measurement value of -3.01 LKFS needs to be output when
a sine waveform of 0 dB and 1 kHz is received.
[0120] Existing research on the size of an audio signal may be
basically divided into two. The first is the development of an
objective audio signal size measurement algorithm that is close to
an audio volume level which his acoustically recognized by a person
as in ITU-R1770-1.
[0121] In the second, in a prior art, the size of an audio signal
was not normalized and transmitted. Accordingly, research on
automatic control of an audio signal size was carried out when
audio files having different sizes were received because an audio
file and a sound source heard by a person have different
volumes.
[0122] In each country, in order to overcome a problem according to
the size of an audio signal, the size of an audio signal is
measured based on ITU-1770-1/2, and a reference value and error
range for the normalization of an audio signal size are proposed
based on the measured size. Today, in Japan, such a method is
actively handled, but in other countries, such a method is in the
early stage or partially applied to only parts, such as commercial
advertisements.
[0123] That is, contents included in the standardization and
regulation acts define a normalization criterion and error range
and an application range, but do not suggest a method for complying
with such a standard. That is, only an object that must be achieved
was suggested, and a method for complying with the standard has not
been proposed.
[0124] Meanwhile, an audio gating method was added to the ITU-R
audio signal size measurement method amended on March, 2011. Audio
gating is a method of measuring an audio volume except a part
having a low audio volume.
[0125] A block for audio volume measurement gating is one cycle,
and 75% of the block overlaps with a neighbor block. Furthermore, a
sample that does not satisfy a block size in the last of a file is
not measured.
[0126] First, the mean square of a block unit is calculated as in
the following equation.
z ij = 1 T g .intg. T g ( f step ) T g ( j step + 1 ) y i 2 t where
step = 1 - overlap and j .di-elect cons. ( 0 , 1 , 2 , , T - T g T
g step ) [ Equation 3 ] ##EQU00005##
[0127] The audio volume of each gated block is calculated as
follows based on the following existing equation.
l i = - 0.691 + 10 log 10 i G i z ij [ Equation 4 ]
##EQU00006##
[0128] If gating is applied to each block, in ITU-R 1770-2, only a
signal of -70 LKFS or higher is taken into consideration, and the
LFKS of a signal to which gating has been applied is measured as in
the following equation.
Gated loudness L KG = - 691 + 10 log 10 i G i ( 1 J g J g z ij )
Where J g = ( i : l j > T r } L r = - 691 + 10 log 10 i G j ( 1
J g J g z ij ) - 10 where J g = { i : l j > - 70 LKFS } [
Equation 5 ] ##EQU00007##
[0129] In the amended method, if the existing pre-filter and RLB
filter are used in the same manner, a method of verifying the
accuracy of an algorithm is also the same.
[0130] When the aforementioned contents are taken into
consideration, contents included in the standardization and
regulation acts so far define a normalization criterion, an error
range, and an application range, but do not clearly disclose a
method for complying with the standard.
[0131] Accordingly, in accordance with a first embodiment of the
present invention to be described later, the size of an audio
signal can be controlled so that it complies with a standard with
respect to a recorded and previously produced broadcasting
program.
[0132] Furthermore, in accordance with a second embodiment of the
present invention to be described later, the size of an audio
signal can be controlled so that it complies with a standard with
respect to a real-time/live-obtained broadcasting program.
[0133] Furthermore, in accordance with a third embodiment of the
present invention to be described later, the size of an audio
signal can be controlled while minimizing the deterioration of
hearing audio sound quality attributable to the normalization of an
audio signal size.
[0134] Furthermore, in accordance with the fourth embodiment of the
present invention to be described later, a new audio control
function in a terminal (TV, a smart phone) can be provided by
taking into consideration the normalization of an audio signal
size.
[0135] FIG. 9 is a diagram illustrating an example of the structure
of a broadcasting system for a recorded and previously produced
broadcasting program.
[0136] Referring to FIG. 9, audio data obtained on the spot is
stored in an Ingest server. The stored file is delivered to an edit
system. In the edit system, edits for each part, such as known
video/audio effects, audio noise removal, and video/audio
synchronization, are performed.
[0137] The data on which the edits for each part have been
performed is finally processed in a complex edit system. A master
control room sends an edited broadcasting program. In view of such
a structure, a task for normalizing the audio signal size of a
recorded and previously produced broadcasting program attributable
to the regulation of an audio signal size may be performed in the
edit system and the complex edit system. Preferably, a step of
producing a file may be performed as the post task of the edit
system because audio data is independently controlled by the edit
system.
[0138] FIG. 10 is a diagram showing a first embodiment of a method
of adjusting an audio signal size.
[0139] In the case of an existing recorded broadcasting program
file, the stored file needs to be analyzed and the normalization of
an audio signal size needs to be performed. Accordingly, referring
to FIG. 10, a demultiplexer may select audio data by demuxing an
existing recorded broadcasting program file (S101).
[0140] Furthermore, a normalization determination unit may
determine whether the audio data has been previously normalized
(S102). In this case, the normalization means normalizing an audio
signal size by adjusting the audio signal size according to a
standardized audio signal size standard as in FIG. 5.
[0141] If the audio data has been previously normalized (S102: Y),
the audio data on which the normalization has been performed may be
stored in a storage device (S103).
[0142] If the audio data has not been previously normalized (S102:
N), an audio decoder may decode the audio data (S104). Furthermore,
an audio signal size controller may perform the normalization of
the audio signal size using the decoded audio data (S105).
Furthermore, an audio encoder may encode the normalized audio data
(S106).
[0143] Meanwhile, a multiplexer may multiplex the encoded audio
data with other data not selected in the demultiplexer (S107).
Accordingly, the storage device may store audio data whose audio
signal size has been normalized (S103).
[0144] The data stored in the storage device may be provided to a
transmission room (S108).
[0145] In this case, a detailed operation of the audio signal size
controller is described in detail with reference to FIGS. 11 and
12.
[0146] Meanwhile, dotted blocks shown in FIG. 10, for example, step
S101, step S104, step S106, and step S107 may be omitted according
to circumstances depending on the format of audio data. For
example, steps S104 and S106 may be omitted depending on whether
audio data has been compressed.
[0147] In accordance with the first embodiment of the present
invention, in order for the audio volume of a recorded and
previously produced broadcasting program to be controlled so that
the audio volume complies with an audio volume standard, first, a
step of producing the broadcasting program is analyzed, and an
essential audio volume may be measured and controlled according to
audio volume regulations.
[0148] FIG. 11 is a detailed diagram illustrating the first
embodiment of the method of adjusting an audio signal size. FIG. 12
is a diagram showing a basic structure of the computation of a
loudness control ratio based on a peak value for adjusting an audio
signal size. In describing FIGS. 11 and 12 hereinafter, a detailed
description of the parts described with reference to FIG. 10 is
omitted, and the remaining parts are described.
[0149] Referring to FIG. 11, control information may be provided in
order to control a recorded broadcasting program.
[0150] First, there may be provided target audio signal size
(target LKFS) values and audio signal size error ranges defined by
several countries according to their regulations and standards. In
general, U.S.A/Japan have a range of 24 LKFS (target LKFS)+/-2 dB
(error range), and Europe has a range of 23 LKFS (target LKFS)+/-1
dB (error range).
[0151] A part related to audio gating was first mentioned in ITU-R
1770-2 and is a method of measuring an LKFS for each block by
applying an overlap and shift method, considering parts having a
low block LKFS as silence, and not using the mean value of such
parts.
[0152] In the case of the ATSC of U.S.A, an AC-3 audio system is
used, and a "dialnorm" parameter is stored as a metadata parameter.
An acoustic audio signal size for an anchor element is inserted
into the dialnorm parameter. That is, the acoustic audio signal
size of a reference point or element is inserted into the part.
[0153] The anchor element is indicative of the standard audio
signal size of the center of a current broadcasting program. The
broadcasting program is finally balanced based on the anchor
element. Furthermore, LKFS values are stored in the dialnorm
parameter. The dialnorm parameter has a variable space of 5 bits
and may store -1.about.-31 LKFS values.
[0154] Meanwhile, in order to measure an audio signal size based on
ITU-R, two filters need to be applied. Accordingly, although an
audio signal size conversion value is extracted by inversely
calculating a difference value between a measured LKFS and a target
LKFS according to the LKFS measurement equation, an accurate value
is unable to be obtained because there is an influence on the two
filters.
[0155] In order to overcome such a problem, in accordance with the
first embodiment of the present invention, an algorithm for
obtaining an audio signal size conversion weighting value factor
suitable for a required target LKFS can be provided by designing a
method using a Peek value.
[0156] As described above, an accurate loudness (LD) control ratio
is unable to be calculated using only the LKFS (original) and
target LKFS of input audio for the aforementioned reason.
[0157] Accordingly, in accordance with the first embodiment of the
present invention, in order to calculate an LD control ratio in
which the two filters are taken into consideration, a Peek-based
control ratio may be calculated using a Peeking method. The Peeking
method may mean a method of obtaining a Peeked LKFS by performing
loudness control on an audio signal using a Peek-based control
ratio. That is, the audio signal size controller may receive input
audio data (S105-1), a Peek weighting value (e.g., 0.9) (S105-2), a
target value LKFS (S105-3), and an LKFS error range (105-4), may
calculate a control ratio (loudness control ratio) for adjusting an
audio signal size (S105-5), and may calculate an LD control ratio
(S105-6). Specifically, a weight factor (LD control ratio) for
approaching the target LKFS may be computed using the LKFS of the
input audio data calculated based on the input audio data, a Peek
LKFS calculated by applying the Peek weighting value to the input
audio data, and a received target LKFS.
new ratio = ( Ori LKFS - peek LKFS ) ( Ori LKFS - Req LKFS ) [
Equation 6 ] ##EQU00008##
[0158] Furthermore, the audio signal size controller may perform
normalization by adjusting the input audio signal size using the
calculated control ratio (LD control ratio).
[0159] In accordance with the first embodiment of the present
invention, an audio signal size may be controlled so that it
complies with a standard with respect to a recorded and previously
produced broadcasting program.
[0160] FIG. 13 is a diagram showing an example of the structure of
a real-time broadcasting system.
[0161] Referring to FIG. 13, the live broadcasting system is quite
different from a recording broadcasting system. A relay system does
not include an Ingest server and does not use a part-based edit
system separately. Instead, in the live broadcasting system, the
relay system integrates such functions and performs the
functions.
[0162] The relay system performs tasks, such as video/audio edit
and effects, and controls an audio sound that is broadcasted live
through a mutual instruction with a studio control room (complex
edit room) which manages the production of the entire program.
[0163] The coordinated broadcasting program is transmitted by a
master control room. Furthermore, a task for an audio sound and
additional tasks, such as the insertion of titles, are performed on
data that is broadcasted live and received through satellites in
the studio control room (complex edit room). The resulting data is
transmitted through the master control room. Accordingly, more
variables are present in order to accurately control the audio
volume of live broadcasting.
[0164] FIG. 14 is a diagram showing a second embodiment.
[0165] Referring to FIG. 14, in a live environment, as described
above, a signal obtained through a microphone and a signal received
through a satellite (hereinafter a live broadcasting signal) may be
taken into consideration. A demultiplexer may demux the live
broadcasting signal and select audio data (S201). Furthermore, an
audio decoder may decode the selected audio data (S203).
[0166] Furthermore, an audio signal size controller may perform the
normalization of an audio signal size using the decoded audio data
(S206). Specifically, the audio signal size controller may analyze
the audio signal size of the live audio data, may control a live
audio signal size, and may perform the normalization. In this case,
the audio signal size controller may perform the normalization
using an audio signal size control value manually received from a
user (S205).
[0167] Furthermore, an audio encoder may encode the audio data on
which the normalization has been performed (S207). Furthermore, a
multiplexer may multiplex the encoded audio data with other data
not selected by the demultiplexer (S208).
[0168] Meanwhile, when the aforementioned data processing is
performed, the data may be provided to a transmission room
(S209).
[0169] In this case, a detailed operation of the audio signal size
controller is described in detail with reference to FIG. 15.
[0170] Meanwhile, dotted blocks shown in the figure, for example,
step S201, step S203, step S205, step S207, and step S208 may be
omitted according to circumstances depending on the format of audio
data. For example, if an input file is audio raw data, audio
decoding is not required. If an audio raw file is required as
output, the audio encoding module is not required. When a signal is
streamed and transmitted, the audio signal size control system
demuxs a file, decodes audio data into an audio signal if the audio
data is a compression bit stream, and bypasses an audio decoding
block if the audio data is raw data. The audio raw signal
automatically controls a live audio signal according to an audio
signal size criterion. The controlled signal is subjected to audio
encoding and file formatting, if necessary, and broadcasted through
a transmission device. Alternatively, an audio raw file may be
output according to a request in output.
[0171] FIG. 15 is a detailed diagram illustrating the second
embodiment. In describing FIG. 15 hereinafter, a detailed
description of the parts described with reference to FIG. 14 is
omitted, and the remaining parts are described.
[0172] Referring to FIG. 15, unlike in an existing system, a
proposed system may have three types of mode in relation to the
normalization of an audio signal size (S206). The first type is
manual loudness control mode, the second type is half automatic
loudness control mode, and the third type is automatic loudness
control mode. The three types of mode can independently operate,
each piece of mode may switch to another mode in the middle, and a
difference between two types of mode according to mode switching
may be compensated for by control of a mode change.
[0173] Manual loudness control mode may be mode in which a person
(e.g., an audio signal editor) manually selects a weighting value
for adjusting an audio signal size (e.g., using various buttons
included in an audio signal processing device) and matches up the
audio signal size with a target audio signal size by scaling an
input audio signal using the selected weighting value. Half
automatic loudness control mode is the same as manual loudness
control mode in that a person manually selects a weighting value
for control, but is different from manual loudness control mode in
that it provides the aforementioned information so that a person
uses information (e.g., a weighting value for scaling an audio
signal size and an input audio signal size) for control of the
audio signal size. Automatic loudness control mode may be mode in
which an audio signal size is automatically controlled so that it
is matched up with a target audio signal size without manual
control of a person. In this case, switching between the pieces of
mode may be performed through a half automatic loudness control
mode selection button, a manual loudness control mode selection
button, and an automatic loudness control mode selection button
provided in the audio signal processing device. Alternatively, the
audio signal processing device may include a single mode switching
button for switching loudness control mode. When the mode switching
button is selected, the pieces of mode may be sequentially
switched.
[0174] Meanwhile, a difference between two pieces of mode according
to mode switching may be compensated for by control of a mode
change. For example, if half automatic loudness control mode
changes to automatic loudness control mode, a Peek weighting value
may be changed. Alternatively, the interpolation of a gate
weighting value described with reference to FIGS. 22 and 23 may be
required. In this case, control of a mode change may include
performing an operation for compensating for such a change.
[0175] Furthermore, in FIG. 15, a weighting value required to be
matched up with a target audio signal size (target LKFS) with
respect to a real-time input audio signal may be calculated through
the aforementioned Peeking method.
[0176] In accordance with a second embodiment of the present
invention, an audio signal size may be controlled with respect to a
real-time/live-obtained broadcasting program so that it complies
with a standard.
[0177] FIG. 16 is a diagram illustrating a method in which a live
LD control step has been added to the last stage of the first
embodiment, the second embodiment. Referring to FIG. 16, a live LD
control step may be further added to the final stage of the method
according to the first embodiment or second embodiment of the
present invention.
[0178] That is, as described above, a file/local broadcasting
program may be stored in the storage device (S103) through local LD
control (S105) and used to be transmitted. Furthermore, as
described above, the live broadcasting program may be processed in
real time and transmitted through live LD control (S206).
[0179] In this case, from a viewpoint of a broadcasting station, in
preparation for regulations, live LD control (S210) may be further
performed on the final stage. That is, from a viewpoint of a
broadcasting station, although a broadcasting program erroneously
inputted in a previous stage is delivered, live LD control (S210)
may be further placed so that the broadcasting program is filtered.
In this case, the live LD control (S210) may include manual
loudness control mode, half automatic loudness control mode, or
automatic loudness control mode. In this case, preferably,
automatic loudness control mode may be used so that 24-hour
processing is automatically possible.
[0180] FIG. 17 is a diagram showing a third embodiment of a method
of compensating for the deterioration of sound quality attributable
to the adjustment of the audio signal size.
[0181] A method of adjusting an audio signal size may be variously
performed depending on the conditions of input data as described
above. In this case, if an audio signal size is matched up with a
target LKFS and an error range, the construction of the audio
signal may feel strong.
[0182] This is an adverse effect according to the normalization of
an audio signal size. In this case, power of influence of audio
normalization and user satisfaction which need to solve adverse
effects attributable to the normalization while achieving the
normalization of the audio signal size can be improved.
[0183] Accordingly, in accordance with the third embodiment of the
present invention, a hearing deterioration compensation module for
compensating for the aforementioned adverse effect may be further
included. That is, referring to FIG. 17, the demultiplexer may
demux existing recorded broadcasting program data or live
broadcasting program data and select audio data (S301).
[0184] Furthermore, the normalization determination unit may
determine whether the audio data has been previously normalized
(S302).
[0185] If normalization has been previously performed on the audio
data (S302: Y), subsequent procedures on the audio data on which
the normalization has been performed may be performed (S303).
[0186] If normalization has not been previously performed on the
audio data (S302: N), the audio decoder may decode the audio data
(S304). Furthermore, editor control, such as Live Audi
Mixing&EQ, may be performed (S305). Furthermore, the audio
signal size controller may perform the normalization of an audio
signal size using the decoded audio data (S306).
[0187] Furthermore, the hearing deterioration compensation module
may compensate for an adverse effect attributable to the
normalization performed by the audio signal size controller (S307).
Furthermore, the audio encoder may encode the audio data on which
acoustic deterioration compensation has been performed (S308).
[0188] Furthermore, the multiplexer may multiplex the encoded audio
data with other data not selected by the demultiplexer (S309).
[0189] Meanwhile, dotted blocks shown in FIG. 17, for example, step
S301, step S304, step S308, and step S309 may be omitted according
to circumstances depending on the format of audio data. For
example, steps S304 and S308 may be omitted depending on whether
the audio data has been compressed.
[0190] In accordance with the third embodiment of the present
invention, an audio signal size can be controlled while minimizing
the deterioration of hearing audio sound quality attributable to
the normalization of the audio signal size.
[0191] Meanwhile, the normalization of an audio signal size
according to the aforementioned method may generate a significant
change of a hearing environment for a digital broadcasting
consumer. Furthermore, services/functions newly required for a
digital broadcasting terminal may be generated because an audio
signal size is normalized. That is, the digital broadcasting
terminal may provide functions related to a broadcasting audio
volume.
[0192] FIG. 18 is a diagram showing a fourth embodiment of a method
of adjusting an audio signal size in a terminal. In describing FIG.
18 hereinafter, a detailed description of the part described with
reference to FIG. 17 (i.e., the processing part (S301.about.S3010)
related to the transmission of a normalized audio signal) is
omitted, and the remaining parts are described.
[0193] Referring to FIG. 18, the terminal may receive a normalized
audio signal (S401), may process the received audio signal (S402),
and may output the processed signal (S403). In this case, the audio
signal process sing (S402) may be controlled for a user-tailored
type, for example. That is, in digital broadcasting, information
about broadcasting is provided to a user, and the use information
of the user is accumulated when the user continues to use the
terminal. The user information is analyzed based on such
information, and a tailored audio sound service can be provided to
the user. Furthermore, a broadcasting information-based user
acoustic service can be directly applied based on user setting
information.
[0194] FIG. 19 is a detailed flowchart illustrating a method of
adjusting an audio signal size in the apparatus for adjusting an
audio signal size in accordance with a first embodiment of the
present invention. Referring to FIG. 19, first, an audio signal may
be received (S501). In this case, the input audio signal may be an
audio signal according to operations (omissible operations), such
as the demuxing and decoding shown in FIGS. 10 to 12, for example.
The audio signal may have various waveforms and may be an audio
signal having a waveform of a type (i.e., prior to normalization)
shown in the front stage of FIG. 5, for example.
[0195] In this case, the audio signal size measurement unit may
measure the LKFS of the input audio signal (original LKFS) using
the method of measuring an audio signal size described with
reference to FIGS. 6 to 8 (S503).
[0196] Furthermore, the audio signal size measurement unit may
measure an initial Peek LKFS (S502). In this case, the initial Peek
LKFS may be measured by scaling the input audio signal using a
preset initial Peek weighting value and measuring the LKFS based on
the scaled audio signal.
[0197] In this case, the preset initial Peek weighting value may be
provided to a broadcasting signal, including an audio signal and a
video signal, in the form of control information. Alternatively,
the preset initial Peek weighting value may be provided as a value
previously stored when the apparatus for adjusting an audio signal
size was designed. Alternatively, the preset initial Peek weighting
value may be provided as input from a user.
[0198] Meanwhile, the weighting value calculation unit may
calculated (S506) an audio signal size (loudness) control ratio
using first (S505: Y), a target value LKFS (S504), a measured
initial Peek LKFS (S502), and the LKFS of a measured input audio
signal (original LKFS) (S503). Specifically, the weighting value
calculation unit may calculate the audio signal size (loudness)
control ratio using Equation 7 below
diff1=original LKFS-peek LKFS
diff2=original LKFS-Target LKFS [Equation 7]
[0199] In this case, the audio signal size (loudness) control ratio
may be diff1/diff2.
[0200] Furthermore, the weighting value calculation unit may
calculate a new Peek weighting value by applying the calculated
audio signal size (loudness) control ratio to Equation 8 below
(S507).
if diff1<diff2
new weight=0.9.sup.diff2/diff2
else
new weight=1.1.sup.diff1/diff2
new_Peek_weight=previous_Peek_weight.times.new_weight [Equation
8]
[0201] In this case, a new_Peek_weighting value may mean a new Peek
weighting value, a previous_Peek_weighting value may mean a Peek
weighting value used prior to the calculation of the
new_Peek_weighting value, and a new_weighting value may mean a
weighting value calculated in Equation 8. For example, in
accordance with Equations 7 and 8, in the first (S505: Y), the new
Peek weighting value may be calculated by multiplexing the initial
Peek weighting value and the new weighting value.
[0202] Meanwhile, in accordance with Equation 8, if a difference
between the original LKFS and a Peek LKFS is smaller than that
between the original LKFS and a target LKFS, a new Peek weighting
value may be calculated by reducing a previous Peek weighting
value. If the difference between the original LKFS and the Peek
LKFS is equal to or greater than that between the original LKFS and
the target LKFS, the new Peek weighting value may be calculated by
increasing a previous Peek weighting value.
[0203] In Equation 8, 0.9 has been used as the weighting value for
reducing the previous Peek weighting value, and 1.1 has been used
as the weighting value for increasing the previous Peek weighting
value. However, the present invention is not limited to such
weighting values, and various weighting values may be used. For
example, for finer control of the audio signal size, 0.99 may be
used as the weighting value for reducing the previous Peek
weighting value, and 1.01 may be used as the weighting value for
increasing the previous Peek weighting value.
[0204] Meanwhile, in this case, the target value LKFS may be
different depending on a target value LKFS determined by global
countries according to their regulations and standards. For
example, as shown in the latter part of FIG. 5 (i.e., after the
normalization), the target value LKFS may be a 24 LKFS. Such a
target value LKFS may be provided to a broadcasting signal,
including an audio signal and a video signal, in the form of
control information. Alternatively, the target value LKFS may be
provided to a broadcasting signal, including an audio signal and a
video signal, as a value previously stored when the apparatus for
adjusting an audio signal size was designed. Alternatively, the
target value LKFS may be provided as input from a user.
[0205] Meanwhile, the audio signal size control unit may control
the audio signal size using the new Peek weighting value calculated
through the aforementioned operation. Specifically, the audio
signal size control unit may control the audio signal size by
scaling the input audio signal (S501) using the calculated new Peek
weighting value (S508).
[0206] Furthermore, the audio signal size measurement unit may
measure the LKFS of an audio signal (new Peek LKFS) (S508) whose
audio signal size has been controlled based on the new Peek
weighting value (S509).
[0207] Meanwhile, the audio signal size control unit may calculate
an LKFS error (S511) by comparing the target value LKFS (S504) with
the measured new Peek LKFS (S509).
[0208] Furthermore, the audio signal size control unit may compare
the LKFS error D with a predetermined error range T (S512). For
example, if the target value LKFS and the audio signal size error
range are 24 LKFS (target LKFS)+/-2 dB (error range), whether a
difference between the target value LKFS and the new Peek LKFS is
greater or equal to an error range may be determined. Such a
predetermined error range (LKFS error range) (S510) may be provided
to a broadcasting signal, including an audio signal and a video
signal, in the form of control information. Alternatively, the
predetermined error range may be provided as a value previously
stored when the apparatus for adjusting an audio signal size was
designed. Alternatively, the predetermined error range may be
provided as input from a user.
[0209] If the LKFS error D is smaller than the predetermined error
range T (S513: Y), the audio signal size control unit may output an
audio signal whose audio signal size has been controlled based on
the new Peek weighting value.
[0210] If the LKFS error D is not smaller than the predetermined
error range T (S513: N), the audio signal size control unit may
perform control so that the aforementioned control operation is
repeated. In this case, if the aforementioned control operation is
repeated, the weighting value calculation unit is not the first
(S505: N) and may calculate a new audio signal size (loudness)
control ratio (S506) using the target value LKFS (S504), the
measured new Peek LKFS (S509), and the measured original LKFS
(S503). In this case, the weighting value calculation unit may
calculate the loudness control ratio using Equation 7. Furthermore,
the weighting value calculation unit may calculate the new Peek
weighting value by applying the calculated audio signal size
(loudness) control ratio to Equation 8 (S507). That is, the
aforementioned operation may be repeated until the audio signal
size satisfies the target value LKFS and the error range.
[0211] Meanwhile, the input audio signal (S501) in accordance with
the first embodiment of the present invention is the audio signal
of a previously produced broadcasting program and may be an audio
signal from the start and end of the broadcasting program.
Accordingly, in accordance with the first embodiment of the present
invention, the audio signal size may be controlled based on the
audio signal size of an audio signal (original LKFS) from the start
and end of the broadcasting program.
[0212] Meanwhile, the encoding operation and the multiplexing
operation (omissible) shown in FIGS. 10 to 12 may be performed on
the output audio signal (S513).
[0213] The apparatus or method for adjusting an audio signal size
or method in accordance with the first embodiment of the present
invention may be included in and performed on the producer side for
producing an audio signal or the supplier side for supplying the
produced audio signal. Alternatively, the apparatus or method for
adjusting an audio signal size in accordance with the first
embodiment of the present invention may be included in or performed
on the user side (e.g., a portable multimedia device, such as an
MP3 player) for receiving and outputting an audio signal.
[0214] In accordance with the first embodiment of the present
invention, an audio signal size may be automatically controlled
with respect to a recorded and previously produced broadcasting
program.
[0215] FIG. 20 is a diagram illustrating a method of measuring an
audio signal size to which the audio gating method described in
ITU-R 1770-2 has been added. In this case, as shown in FIG. 20, the
audio gating method may include measuring the LKFS of a gate block
1, measuring the LKFS of a gate block 2 using the overlap and shift
method, measuring an LKFS for each gate block by repeating the
overlap and shift method, performing bundle processing if the LKFS
of the measured gate block is less than a threshold LKFS (-70 LKFS
in the ITU-R 1770-2), and performing audio signal size measurement
on an audio signal to which gating has been applied.
[0216] In this case, with respect to the aforementioned gate block,
in the ITU-R 1770-2, the gate block has a gate size of 0.4 s and
has a structure overlapped by 75%.
[0217] Meanwhile, in a real-time/live environment, an audio signal
is obtained for each gate block. The LKFS of each gate block is
measured using Equation 4 to 5. A new Peek weighting value for
adjusting an audio signal size for each gate block may be
calculated using the aforementioned method of FIG. 19. In this
case, if the audio signal size is controlled for each gate block
using the new Peek weighting value calculated for each gate block,
a discontinuous sound may be generated due to a difference in the
weighting value between neighboring gate blocks.
[0218] In order to solve such a problem, the method of adjusting an
audio signal size n accordance with the fifth embodiment of the
present invention may perform the following processing.
[0219] FIG. 21 is a diagram illustrating gate handover in order to
describe a method of adjusting an audio signal size in accordance
with a fifth embodiment of the present invention. Referring to FIG.
21, the gate size of a region which is not overlapped with a gate
block may be 4800 samples, for example. Furthermore, if a codec,
such as AAC or AC-3, is used, a single frame size that determines
one data size may be 1024 samples. In this case, gate handover in
which a single frame overlaps with two gate blocks may be
generated.
[0220] FIG. 22 is a diagram illustrating a method of adjusting an
audio signal size in accordance with the fifth embodiment of the
present invention. Referring to FIG. 22, the method of adjusting an
audio signal size in accordance with the fifth embodiment of the
present invention may include adjusting an audio signal size by
interpolating a gate weighting value from a frame in which gate
handover is generated. In this case, the gate weighting value may
be a new Peek weighting value calculated using the aforementioned
method of FIG. 19 with respect to each gate block.
[0221] In accordance with the fifth embodiment of the present
invention, gate delay attributable to the interpolation of a gate
weighting value is not generated. That is, at a point of time at
which data is received in a frame in which gate handover is
generated, the gate weighting values of two gate blocks overlapping
across the frame in which gate handover is generated can be
previously calculated. Accordingly, a gate weighting value can be
interpolated without delay from the frame in which gate handover is
generated using the gate weighting values of the two gate
blocks.
[0222] Meanwhile, in accordance with the fifth embodiment of the
present invention, various interpolation methods may be used in
order to interpolate a gate weighting value. For example, the
present linear interpolation method may be used. The present linear
interpolation method is described in detail with reference to FIG.
23.
[0223] FIG. 23 is a diagram illustrating linear interpolation, that
is, an example of interpolation in accordance with a fifth
embodiment of the present invention. Referring to FIG. 23, linear
interpolation, such as Equation below, may be used.
W i = W G 1 + W G 1 - W G 2 InterFrame .times. i , i = 1 InterFrame
- 1 [ Equation 9 ] ##EQU00009##
[0224] In Equation 9, W.sub.G1 is the gate weighting value of a
gate block 1, W.sub.G2 is the gate weighting value of a gate block
2, i is the number of gate weighting values to be interpolated, and
an interframe is the number of frames from an interpolation start
frame to an interpolation end frame.
[0225] For example, if Equation 9 is applied using the number of
interframes of 3, as shown in FIG. 22, a gate weighting value to be
applied to two frames (weighting values W.sub.1 and W.sub.2
indicated by a red color) may be calculated. That is, the number of
interpolated gate weighting values may be variably controlled by
selectively controlling the number of interframes.
[0226] Meanwhile, in accordance with the fifth embodiment of the
present invention, the gate weighting value interpolation method
may be applied to all methods for adjusting an audio signal size
using a gate weighting value. For example, the gate weighting value
interpolation method may be applied to a previously recorded
broadcasting program and may control an audio signal size and may
be applied to a live broadcasting program and may control an audio
signal size.
[0227] Furthermore, the apparatus or method for adjusting an audio
signal size in accordance with the fifth embodiment of the present
invention may be included in or performed on the producer side for
producing an audio signal or the supplier side for supplying the
produced audio signal. Alternatively, the apparatus or method for
adjusting an audio signal size in accordance with the fifth
embodiment of the present invention may be included in and
performed on the user side (e.g., a portable multimedia device,
such as an MP3 player) for receiving and outputting an audio
signal.
[0228] In accordance with the fifth embodiment of the present
invention, gate delay attributable to the interpolation of a gate
weighting value may not be generated by interpolating a gate
weighting value from a frame in which gate handover is
generated.
[0229] Furthermore, the number of interpolated gate weighting
values may be variably controlled.
[0230] FIG. 24 is a diagram showing an example of information
provided in half automatic loudness control mode of the second
embodiment of the present invention. In this case, half automatic
loudness control mode is the same as manual loudness control mode
in that a person manually selects a weighting value for control,
but may be different from manual loudness control mode in that it
provides the aforementioned information so that a person may use
information for control of an audio signal size.
[0231] In such half automatic loudness control mode, information
for adjusting an audio signal size, as shown in FIG. 24, at least
one of a momentary LKFS 601, a short term (3 s) LKFS 602, an
integrated LKFS 603, a played LKFS 604, the remained LKFS 605, and
the recommended control factor 606 may be included.
[0232] In this case, the momentary LKFS 601 may be a weighting
value for controlling a calculated audio signal size using the LKFS
of an input audio signal (e.g., the LKFS of the input audio signal
for 0.4 S as in FIG. 20) with respect to a gate block. In the short
term (3 s), the LKFS 602 may be a weighting value for adjusting a
calculated audio signal size using the LKFS of an input audio
signal for 3 S with respect to a gate block. The integrated LKFS
603 may be a weighting value for adjusting a calculated audio
signal size using the LKFS of an input audio signal so far with
respect to a gate block. The played LKFS 604 may be a weighting
value for adjusting a calculated audio signal size using the LKFS
of an input audio signal output so far with respect to a gate
block. The remained LKFS 605 may be a weighting value for adjusting
an audio signal size calculated using an insufficient or exceeded
LKFS of the played LKFS 604 versus a target value LKFS with respect
to a gate block. The recommended control factor 606 may be a
weighting value for adjusting an audio signal size calculated using
the remained LKFS 605 with respect to a gate block.
[0233] The momentary LKFS 601, the short term (3 s) LKFS 602, and
the integrated LKFS 603 may be measured using Equation 4 to 5.
[0234] Meanwhile, the played LKFS 604 may be different from the
integrated LKFS 603, that is, the LKFS of an input audio signal
whose audio signal size has not been controlled, in that an output
audio signal (i.e., the audio signal size may be controlled by the
aforementioned operations of FIGS. 22 and 23 and output to an audio
playback device) is an audio signal whose audio signal size has
been controlled.
[0235] The played LKFS 604 may be calculated using Equation 10
below.
x : filtered signal by tow filters pSum = i M x i 2 pMean = 1 M i M
x i 2 played_mean = previous_Mean .times. ( N - 1 ) + pMean N
PlayedLKFS = - 0.691 .times. 10 .times. log 10 ( played mean ) [
Equation 10 ] ##EQU00010##
[0236] In this case, x is an audio signal output so far with
respect to a signal that has passed through the two filters defined
in the LKFS measurement algorithm. M is the number of samples of a
gate block. N is the number of gate blocks to which an audio signal
has been inputted so far.
[0237] That is, referring to FIG. 20, in a real-time/live
environment, since an audio signal is inputted to each gate block,
as in Equation 10, the mean played_mean of output audio signals so
far needs to be calculated. Accordingly, when the mean played_mean
is obtained, the played LKFS 604 may be measured by applying the
equation described the ITU-R 1770-2.
[0238] Meanwhile, when calculation is performed as in Equation 10,
if the data of an audio signal is increased, an N value becomes
very high. In the case of a fixed-point processor, a result of the
multiplication of previous_Mean and N-1 may exceed a processor
range. Furthermore, there may be a significant even in a floating
point processor. It may be a burden on the processing of the
processor and the storage capacity of memory.
[0239] In order to supplement such a problem, in accordance with an
embodiment of the present invention, as in Equation 11 below, the
mean present_mean of output audio signals so far may be calculated
using a method of dividing N not a method of multiplying N. In this
case, the played LKFS 604 may be measured by applying the
calculated present_mean to the mean played_mean of Equation 10. In
this case, a burden on the processing of the processor and the
storage capacity of memory can be reduced.
if previous Mean > pMean present_Mean = previous_Mean -
previous_Mean - pMean N else present_Mean = previous_Mean -
previous_Mean - pMean N [ Equation 11 ] ##EQU00011##
[0240] FIG. 25 is a diagram showing a method of calculating a
recommended control factor that belongs to information provided in
half automatic loudness control mode of the second embodiment of
the present invention. Referring to FIG. 25, the remained LKFS 605
may be calculated using Equation 12 below, and the recommended
control factor 606 may be calculated using the measured remained
LKFS 605.
Remained_LKFS = Target_LKFS - ( Played_LKFS .times. Ps Ts ) Ts - Ps
Ts [ Equation 12 ] ##EQU00012##
[0241] In this case, the remained LKFS 605 may be calculated using
the played LKFS 604, the target LKFS 607, a total time of an audio
signal (total play time (Ts)) 608, and the current time of the
output audio signal (played time (Ps)) 609. Referring to Equation
12, the remained LKFS 605 may means an insufficient or exceeded
LKFS of the played LKFS 604 compared to a target value LKFS.
[0242] The recommended control factor 606 may be a weighting value
for adjusting an audio signal size using the remained LKFS 605.
That is, the remained LKFS 605 means an insufficient or exceeded
LKFS of the played LKFS 604 compared to the target value LKFS 607.
The weighting value calculation unit may calculate a weighting
value at which a total audio signal size of an audio signal to be
output becomes the target value LKFS 607 using the remained LKFS
605.
[0243] Meanwhile, in half automatic loudness control mode, such as
the aforementioned momentary LKFS 601, short term (3 s) LKFS 602,
integrated LKFS 603, played LKFS 604, remained LKFS 605, and
recommended control factor 606, information for adjusting an audio
signal size may be provided through a display screen included in
the apparatus for adjusting an audio signal size.
[0244] In accordance with an embodiment of the present invention, a
user can control an audio signal size more easily in a
real-time/live environment because information for adjusting an
audio signal size is provided.
[0245] FIG. 26 is a diagram showing a method of adjusting an audio
signal size in automatic loudness control mode of the second
embodiment of the present invention. In this case, automatic
loudness control mode may be mode in which an audio signal size is
automatically matched up with a target audio signal size without
manual control of a person. In automatic loudness control mode, a
gate weighting value to be applied for each gate block needs to be
automatically calculated.
[0246] To this end, in accordance with an embodiment of the present
invention, in automatic loudness control mode, the weighting value
calculation unit may automatically calculate a gate weighting value
for scaling an audio signal for each gate using an input audio
signal size (original LKFS) obtained for each gate block in real
time, an audio signal size (Peek LKFS) obtained by scaling the
input audio signal obtained for each gate block in real time using
a Peek weighting value, and a mapped LKFS calculated by applying an
input audio signal size (original LKFS) to a mapping curve. The
audio signal size control unit may control an audio signal size
using the calculated gate weighting value.
[0247] In this case, the mapping curve may be a curve in which an
overall size deviation of an output audio signal is maintained
while making a total audio signal size of the audio signal inputted
from the start and end of the audio signal a target audio signal
size value (target LKFS) (e.g., -24 LKFS). That is, if a
normalization task for making the total audio signal size of the
input audio signal a target audio signal size value (e.g., -24
LKFS) is performed, a block having a small audio signal size for
each gate block is increased, and a block having a large audio
signal size for each gate block is decreased. In this case, there
may be a problem in that a deviation of a sound size delivered to a
person's ear is reduced. Accordingly, in accordance with an
embodiment of the present invention, a deviation of a sound size
delivered to a person's ear can be maintained using the mapping
curve that maintains an overall size deviation of an audio
signal.
[0248] Meanwhile, the weighting value calculation unit may
calculate diff1/diff2, that is, an audio signal size (loudness)
control ratio by applying the mapped LKFS to the target LKFS of
Equation 7 and may calculate a new gate weighting value by applying
the calculated audio signal size (loudness) control ratio to
Equation 8.
[0249] Furthermore, the audio signal size control unit may control
an audio signal size using a gate weighting value for scaling an
audio signal calculated for each gate block. A detailed description
of such an operation has been described in detail with reference to
FIG. 19 and thus omitted.
[0250] FIG. 27 is a diagram showing a method of designing a mapping
curve for calculating a mapping audio signal size (mapped LKFS)
according to FIG. 26. In this case, a mapping curve is a curve
indicative of the relationship between an input audio signal size
(original LKFS) and a mapping audio signal size (mapped LKFS) for
each gate block. Referring to FIG. 27(a), the mapping curve may be
designed by separating a major LKFS region and a non-major LKFS
region (low LKFS region).
[0251] In this case, the non-major LKFS region (low LKFS region)
may be an LKFS region in which an input audio signal size delivered
to a person's ear is smaller than a predetermined value. The major
LKFS region may be an LKFS region in which an input audio signal
size delivered to a person's ear is equal to or greater than the
predetermined value.
[0252] That is, referring to FIG. 27 (b), the major LKFS region may
design a mapping curve based on a variable weighting value, and the
non-major LKFS region may design a mapping curve in a linear
form.
[0253] In this case, the mapping curve for the major LKFS region
may be designed using Equation 13 below.
oLKFS i = 1 ( 1 + exp ( - LKFS i .times. w ) ) [ Equation 13 ]
##EQU00013##
[0254] In this case, iLKFS is an input audio signal size (original
LKFS) for each gate, oLKFS is an audio signal size (mapped LKFS)
mapped to each gate, and w is a weighting value. Accordingly, the
variable mapping curve for the major LKFS region can be generated.
The mapping curve may be controlled through control of the mapping
curve.
[0255] In accordance with an embodiment of the present invention,
an input audio signal is normalized using a mapping curve and
output. Accordingly, the audio signal that is normalized and output
can maintain a size deviation of the input audio signal, and thus a
deviation of a sound size delivered to a person's ear can be
maintained.
[0256] FIGS. 28 to 30 are diagrams showing a comparison between the
waveform of an input audio signal and the waveform of a normalized
audio signal.
[0257] FIG. 28(a) is a diagram showing the waveform of an input pop
audio signal, and FIG. 28(b) is a diagram showing the waveform of a
normalized pop audio signal. From FIG. 28, it may be seen that the
input pop audio signal size was -22.23 LKFS, but the normalized pop
audio signal size becomes -22.72 LKFS through the aforementioned
normalization operation and thus the input pop audio signal size
have been normalized within a target audio signal size and an error
range.
[0258] FIG. 29(a) is a diagram showing the waveform of an input
K-pop audio signal, and FIG. 29(b) is a diagram showing the
waveform of a K-pop normalized audio signal. From FIG. 29, it may
be seen that the input K-pop audio signal size was -8.9 LKFS, but
the normalized K-pop audio signal size becomes -23.28 LKFS through
the aforementioned normalization operation and thus the input K-pop
audio signal has been normalized within a target audio signal size
and an error range.
[0259] FIG. 30(a) is a diagram showing the waveform of an input
classical audio signal, and FIG. 30(b) is a diagram showing the
waveform of a normalized classical audio signal. From FIG. 30, it
may be seen that the input classical audio signal size was -26
LKFS, but the normalized classical audio signal size becomes -25.34
LKFS through the aforementioned normalization operation and thus
the input classical audio signal size has been normalized within a
target audio signal size and an error range.
[0260] Meanwhile, the aforementioned methods according to various
embodiments of the present invention may be produced in the form of
a program that is to be executed by a computer and may be stored in
a computer-readable recording medium. Multimedia data having a data
structure according to the present invention may also be stored in
computer-readable recording media. The computer-readable recording
media include all types of storage devices in which data readable
by a computer system is stored. The computer-readable recording
media may include ROM, RAM, CD-ROM, a magnetic tape, a floppy disk,
and an optical data storage device, for example. Furthermore, the
computer-readable recording media includes media implemented in the
form of carrier waves (e.g., transmission through the
Internet).
[0261] Furthermore, the computer-readable recording medium may be
distributed over computer systems connected over a network, and the
processor-readable code may be stored and executed in a distributed
manner. Furthermore, functional programs, code, and code segments
for implementing the method may be easily reasoned by programmers
in the art to which the present invention pertains.
[0262] Furthermore, although the preferred embodiments of the
present invention have been illustrated and described above, the
present invention is not limited to the aforementioned specific
embodiments, and those skilled in the art to which the present
invention pertains may modify the present invention in various ways
without departing from the gist of the present invention written in
the claims. Such modified embodiments should not be individually
understood from the technical spirit or prospect of the present
invention.
* * * * *